Oops forgot to post this link to a recent thread on the P block over at the FE Forum. There's a link to an auction for an NOS (with original box) P sideoiler block AND NOS NIB steel crank with a price of $6,500.
FordFE.com Classifieds: NOS 427 Block and NOS 427 Steel Crank in original Boxes (Mine)
AFAIK, they are still available.